Method of making an aromatic polyether composition using phosphazenium salt phase transfer catalysts

ABSTRACT

A method for carrying out a chemical reaction between at least two reactants occupying separate phases within a multiphase reaction mixture has been discovered in which at least one phosphazenium salt is employed as a phase transfer catalyst. The remarkable utility of phosphazenium salts as phase transfer catalysts is illustrated by the preparation of aromatic ethers. The phosphazenium salt phase transfer catalysts are shown to be especially useful in the preparation of aromatic polyethers such as polyether sulfones.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 11/651,167 filed on Jan. 9, 2007. U.S. patent application Ser.No. 11/651,167 is a divisional application of 10/950,874 filed on Sep.24, 2004, now abandoned. U.S. patent application Ser. Nos. 11/651,167and 10/950,874 are both incorporated by reference herein in theirentirety.

BACKGROUND OF THE INVENTION

This invention relates to use of phosphazenium salts as phase transfercatalysts. In one aspect the invention relates to a method of makingaromatic ethers. More particularly, the method relates to a method ofpreparing aromatic ethers using exceptionally stable phosphazenium saltphase transfer catalysts.

Various types of aromatic ethers have gained prominence due to theirutility in diverse fields as agricultural chemistry, medicinal chemistryand polymer chemistry. One class of aromatic ethers, aromatic polyethers(e.g. See for example polyethersulfones, polyetherimides, andpolyetherketones), are important engineering resins due to theirexceptional chemical and physical properties.

Aromatic ethers are typically prepared by synthetic methodologyinvolving the reaction of the salt of an aromatic hydroxy compound withan aromatic compound comprising at least one suitable leaving group. Inone general methodology, aromatic ethers are prepared in a nucleophilicaromatic substitution reaction between a nucelophilic aromatic hydroxycompound and an electrophonic aromatic compound comprising at least onesuitable leaving group, the reaction being mediated by a stoichiometricamount of a basic reactant such as an alkali metal hydroxide or alkalimetal carbonate. Typically, such nucleophilic aromatic substitutionreactions must be carried out in polar aprotic solvents such asdimethylformamide, dimethylacetamide, N-methylpyrrolidinone, dimethylsulfoxide, or sulfolane in order to achieve synthetically useful ratesof conversion of starting materials to product aromatic ethers. In suchcases, drying, recovery, and reuse of the solvent is cumbersome andexpensive.

Various phase transfer catalysts (PTC's) are known to acceleratereaction rates of chemical reactions generally. Phase transfer catalystsare typically most effective when the chemical reaction involvesreactants which tend to segregate into separate phases. Among otherbenefits, the use of phase transfer catalysts is known to enable the useof solvents in which one or more of the reactants is insoluble in theabsence of the phase transfer catalyst.

Known phase transfer catalysts include quaternary ammonium salts,quaternary phosphonium salts, and hexaalkylguanidinium salts. Of theknown phase transfer catalysts, quaternary ammonium salts are stable atambient temperature, but decompose rapidly at temperatures in excess ofabout 100° C. Quaternary phosphonium salts are more stable, but theiruse typically results in a lower reaction rate relative to the reactionrate observed in the corresponding reaction in which a quaternaryammonium salt phase transfer catalyst is employed. Thus, higher levelsof phosphonium salt phase transfer catalyst must be used in order toachieve reaction rates comparable to reaction rates attained usingquaternary ammonium salt phase transfer catalysts. Hexaalkylguanidiniumsalts are effective phase transfer catalysts but nonetheless are subjectto decomposition at higher temperatures.

Much attention has been directed in recent years to organic reactions inheterogeneous systems, employing a phase transfer catalyst whichfacilitates the migration of a reactant into a phase from which it isnormally absent. Many types of phase transfer catalysts are known to beeffective under such conditions, including quaternary ammonium andphosphonium salts as disclosed in U.S. Pat. No. 4,273,712. Additionally,various bis-quaternary ammonium or phosphonium salts have been used asdisclosed in U.S. Pat. No. 4,554,357; and aminopyridinium salts havebeen used as disclosed in U.S. Pat. Nos. 4,460,778, 4,513,141 and4,681,949. Hexaalkylguanidinium salts, and their bis-salt analogues havebeen used as phase transfer catalysts as disclosed in U.S. Pat. Nos.5,132,423; 5,116,975; and 5,081,298.

Nucleophilic aromatic substitution reactions, also referred to as“nucleophilic aromatic displacement reactions” often require heating ahighly insoluble salt of an aromatic hydroxy compound with a solublearomatic compound comprising at least one suitable leaving group in arelatively nonpolar solvent such as o-dichlorobenzene (o-DCB) in thepresence of a phase transfer catalyst. Frequently, for syntheticallyuseful reaction rates to be achieved, the reaction mixture must beheated to a temperature at which the phase transfer catalyst decomposes.While a prodigious technical effort has been expended in the developmentof more thermally stable phase transfer catalysts (See for example thedevelopment of 4-dialkylaminopyridinium salt catalysts andhexaalkylguanidinium salt catalysts), improved phase transfer catalystthermal stability remains an important objective.

It would be highly desirable, therefore, to discover phase transfercatalysts having improved stability that could be used under a widevariety of reaction conditions, including the formation of aromaticethers.

BRIEF SUMMARY OF THE INVENTION

In one aspect the present invention provides phosphazenium salts andtheir use as phase transfer catalysts generally.

In another aspect the present invention provides a method for makingaromatic ethers comprising contacting in a reaction mixture the salt ofat least one aromatic hydroxy compound with at least one aromaticcompound comprising at least one leaving group, said contacting beingcarried out in the presence of a phosphazenium salt having structure I

wherein n is an integer from zero to about 10, R¹ and R² areindependently selected from the group consisting of C₁-C₂₀ aliphaticradicals, C₃-C₂₀ cycloaliphatic radicals, and C₄-C₂₀ aromatic radicals,and wherein said R¹ and R² may be linked together form a cyclicstructure comprising at least one nitrogen atom, and wherein X⁻ isselected from the group consisting of monovalent inorganic anions,monovalent organic anions, polyvalent inorganic anions, polyvalentorganic anions, and mixtures thereof.

In another aspect the present invention provides a method for makingaromatic polyether compositions, said method comprising contacting in areaction mixture the salt of at least one aromatic dihydroxy compoundwith at least one aromatic compound bearing at least two leaving groups,said contacting being carried out in the presence of a phosphazeniumsalt having structure I.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the reaction kinetics observed in a series ofreactions involving the 4-chlorophenyl phenyl sulfone and the disodiumsalt of bisphenol A in the presence of a phosphazenium salt phasetransfer catalyst at various temperatures.

FIG. 2 compares the reaction kinetics observed in a series of reactionsinvolving the 4-chlorophenyl phenyl sulfone and the disodium salt ofbisphenol A in the presence of either a guanidinium salt phase transfercatalyst, or a phosphazenium salt phase transfer catalyst.

FIG. 3 illustrates the rate of polymerization observed in a reactionbetween bis(4-chlorophenyl) sulfone and the disodium salt of bisphenol Ain the presence of 2 mole percent phosphazenium salt phase transfercatalyst at 180° C.

FIG. 4 illustrates the rate of polymerization observed in a reactionbetween bis(4-chlorophenyl) sulfone and the disodium salt of bisphenol Ain the presence of 1 mole percent phosphazenium salt phase transfercatalyst at 200° C.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be understood more readily by reference to thefollowing detailed description of preferred embodiments of the inventionand the examples included therein. In the following specification andthe claims which follow, reference will be made to a number of termswhich shall be defined to have the following meanings:

The singular forms “a”, “an” and “the” include plural referents unlessthe context clearly dictates otherwise.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where the event occurs and instances where it does not.

As used herein the term “BPA” refers to bisphenol A.

As used herein the term “aliphatic radical” refers to a radical having avalence of at least one comprising a linear or branched array of atomswhich is not cyclic. The array may include heteroatoms such as nitrogen,sulfur, silicon, selenium and oxygen or may be composed exclusively ofcarbon and hydrogen. Aliphatic radicals may be “substituted” or“unsubstituted”. A substituted aliphatic radical is defined as analiphatic radical which comprises at least one substituent. Asubstituted aliphatic radical may comprise as many substituents as thereare positions available on the aliphatic radical for substitution.Substituents which may be present on an aliphatic radical include butare not limited to halogen atoms such as fluorine, chlorine, bromine,and iodine. Substituted aliphatic radicals include trifluoromethyl,hexafluoroisopropylidene, chloromethyl; difluorovinylidene;trichloromethyl, bromoethyl, bromotrimethylene (e.g. —CH₂CHBrCH₂—), andthe like. For convenience, the term “unsubstituted aliphatic radical” isdefined herein to encompass, as part of the “linear or branched array ofatoms which is not cyclic” comprising the unsubstituted aliphaticradical, a wide range of functional groups. Examples of unsubstitutedaliphatic radicals include allyl, aminocarbonyl (i.e. —CONH₂), carbonyl,dicyanoisopropylidene (i.e. —CH₂C(CN)₂CH₂—), methyl (i.e. —CH₃),methylene (i.e. —CH₂—), ethyl, ethylene, formyl, hexyl, hexamethylene,hydroxymethyl (i.e. —CH₂OH), mercaptomethyl (i.e. —CH₂SH), methylthio(i.e. —SCH₃), methylthiomethyl (i.e. —CH₂SCH₃), methoxy,methoxycarbonyl, nitromethyl (i.e. —CH₂NO₂), thiocarbonyl,trimethylsilyl, t-butyldimethylsilyl, trimethyoxysilypropyl, vinyl,vinylidene, and the like. Aliphatic radicals are defined to comprise atleast one carbon atom. A C₁-C₁₀ aliphatic radical includes substitutedaliphatic radicals and unsubstituted aliphatic radicals containing atleast one but no more than 10 carbon atoms.

As used herein, the term “aromatic radical” refers to an array of atomshaving a valence of at least one comprising at least one aromatic group.The array of atoms having a valence of at least one comprising at leastone aromatic group may include heteroatoms such as nitrogen, sulfur,selenium, silicon and oxygen, or may be composed exclusively of carbonand hydrogen. As used herein, the term “aromatic radical” includes butis not limited to phenyl, pyridyl, furanyl, thienyl, naphthyl,phenylene, and biphenyl radicals. As noted, the aromatic radicalcontains at least one aromatic group. The aromatic group is invariably acyclic structure having 4n+2 “delocalized” electrons where “n” is aninteger equal to 1 or greater, as illustrated by phenyl groups (n=1),thienyl groups (n=1), furanyl groups (n=1), naphthyl groups (n=2),azulenyl groups (n=2), anthraceneyl groups (n=3) and the like. Thearomatic radical may also include nonaromatic components. For example, abenzyl group is an aromatic radical which comprises a phenyl ring (thearomatic group) and a methylene group (the nonaromatic component).Similarly a tetrahydronaphthyl radical is an aromatic radical comprisingan aromatic group (C₆H₃) fused to a nonaromatic component —(CH₂)₄—.Aromatic radicals may be “substituted” or “unsubstituted”. A substitutedaromatic radical is defined as an aromatic radical which comprises atleast one substituent. A substituted aromatic radical may comprise asmany substituents as there are positions available on the aromaticradical for substitution. Substituents which may be present on anaromatic radical include, but are not limited to halogen atoms such asfluorine, chlorine, bromine, and iodine. Substituted aromatic radicalsinclude trifluoromethylphenyl, hexafluoroisopropylidenebis(4-phenyloxy)(i.e. —OPhC(CF₃)₂PhO—), chloromethylphenyl; 3-trifluorovinyl-2-thienyl;3-trichloromethylphenyl (i.e. 3-CCl₃Ph-), bromopropylphenyl (i.e.BrCH₂CH₂CH₂Ph-), and the like. For convenience, the term “unsubstitutedaromatic radical” is defined herein to encompass, as part of the “arrayof atoms having a valence of at least one comprising at least onearomatic group”, a wide range of functional groups. Examples ofunsubstituted aromatic radicals include 4-allyloxyphenoxy, aminophenyl(i.e. H₂NPh-), aminocarbonylphenyl (i.e. NH₂COPh-), 4-benzoylphenyl,dicyanoisopropylidenebis(4-phenyloxy) (i.e. —OPhC(CN)₂PhO—),3-methylphenyl, methylenebis(4-phenyloxy) (i.e. —OPhCH₂PhO—),ethylphenyl, phenylethenyl, 3-formyl-2-thienyl, 2-hexyl-5-furanyl;hexamethylene-1,6-bis(4-phenyloxy) (i.e. —OPh(CH₂)₆PhO—);4-hydroxymethylphenyl (i.e. 4-HOCH₂Ph-), 4-mercaptomethylphemyl (i.e.4-HSCH₂Ph-), 4-methylthiophenyl (i.e. 4-CH₃SPh-), methoxyphenyl,methoxycarbonylphenyloxy (e.g. methyl salicyl), nitromethylphenyl (i.e.-PhCH₂NO₂), trimethylsilylphenyl, t-butyldimethylsilylphenyl,vinylphenyl, vinylidenebis(phenyl), and the like. The term “a C₃-C₁₀aromatic radical” includes substituted aromatic radicals andunsubstituted aromatic radicals containing at least three but no morethan 10 carbon atoms. The aromatic radical 1-imidazolyl (C₃H₂N₂—)represents a C₃ aromatic radical. The benzyl radical (C₇H₈—) representsa C₇ aromatic radical.

As used herein the term “cycloaliphatic radical” refers to a radicalhaving a valence of at least one, and comprising an array of atoms whichis cyclic but which is not aromatic. As defined herein a “cycloaliphaticradical” does not contain an aromatic group. A “cycloaliphatic radical”may comprise one or more noncyclic components. For example, acyclohexylmethy group (C₆H₁₁CH₂—) is an cycloaliphatic radical whichcomprises a cyclohexyl ring (the array of atoms which is cyclic butwhich is not aromatic) and a methylene group (the noncyclic component).The cycloaliphatic radical may include heteroatoms such as nitrogen,sulfur, selenium, silicon and oxygen, or may be composed exclusively ofcarbon and hydrogen. Cycloaliphatic radicals may be “substituted” or“unsubstituted”. A substituted cycloaliphatic radical is defined as acycloaliphatic radical which comprises at least one substituent. Asubstituted cycloaliphatic radical may comprise as many substituents asthere are positions available on the cycloaliphatic radical forsubstitution. Substituents which may be present on a cycloaliphaticradical include but are not limited to halogen atoms such as fluorine,chlorine, bromine, and iodine. Substituted cycloaliphatic radicalsinclude trifluoromethylcyclohexyl,hexafluoroisopropylidenebis(4-cyclohexyloxy) (i.e.—OC₆H₁₁C(CF₃)₂C₆H₁₁O—), chloromethylcyclohexyl;3-trifluorovinyl-2-cyclopropyl; 3-trichloromethylcyclohexyl (i.e.3-CCl₃C₆H₁₁—), bromopropylcyclohexyl (i.e. BrCH₂CH₂CH₂C₆H₁₁—), and thelike. For convenience, the term “unsubstituted cycloaliphatic radical”is defined herein to encompass a wide range of functional groups.Examples of unsubstituted cycloaliphatic radicals include4-allyloxycyclohexyl, aminocyclohexyl (i.e. H₂N C₆H₁₁—),aminocarbonylcyclopenyl (i.e. NH₂COC₅H₉—), 4-acetyloxycyclohexyl,dicyanoisopropylidenebis(4-cyclohexyloxy) (i.e. —OC₆H₁₁C(CN)₂C₆H₁₁O—),3-methylcyclohexyl, methylenebis(4-cyclohexyloxy) (i.e.—OC₆H₁₁CH₂C₆H₁₁O—), ethylcyclobutyl, cyclopropylethenyl,3-formyl-2-terahydrofuranyl, 2-hexyl-5-tetrahydrofuranyl;hexamethylene-1,6-bis(4-cyclohexyloxy) (i.e. —OC₆H₁₁(CH₂)₆ C₆H₁₁O—);4-hydroxymethylcyclohexyl (i.e. 4-HOCH₂C₆H₁₁-),4-mercaptomethylcyclohexyl (i.e. 4-HSCH₂C₆H₁₁—), 4-methylthiocyclohexyl(i.e. 4-CH₃SC₆H₁₁—), 4-methoxycyclohexyl, 2-methoxycarbonylcyclohexyloxy(2-CH₃OCO C₆H₁₁O—), nitromethylcyclohexyl (i.e. NO₂CH₂C₆H₁₀—),trimethylsilylcyclohexyl, t-butyldimethylsilylcyclopentyl,4-trimethoxysilyethylcyclohexyl (e.g. (CH₃O)₃SiCH₂CH₂C₆H₁₀—),vinylcyclohexenyl, vinylidenebis(cyclohexyl), and the like. The term “aC₃-C₁₀ cycloaliphatic radical” includes substituted cycloaliphaticradicals and unsubstituted cycloaliphatic radicals containing at leastthree but no more than 10 carbon atoms. The cycloaliphatic radical2-tetrahydrofuranyl (C₄H₇O—) represents a C₄ cycloaliphatic radical. Thecyclohexylmethyl radical (C₆H₁₁CH₂—) represents a C₇ cycloaliphaticradical.

As noted, the present invention provides phosphazenium salts and theiruse as phase transfer catalysts generally. Thus, it has been discoveredthat phosphazenium salts make outstanding phase transfer catalysts, inpart due to the very high level of thermal stability phosphazenium saltsexhibit. In one embodiment, the present invention provides a method forcarrying out a chemical reaction between at least two reactantsoccupying separate phases within a multiphase reaction mixturecomprising at least one phosphazenium salt phase transfer catalyst.Although, the utility of phosphazenium salts as phase transfer catalystsis illustrated experimentally herein in terms of multiphase reactionsinvolving the formation aryl ethers, the present invention encompassesthe use generally of phosphazenium salts as phase transfer catalysts inmultiphase reactions. Thus, in the description and experimental detailswhich follow, the use of phosphazenium salts as phase transfer catalystsis illustrated by chemistry related to the formation of aromatic ethersbut is in no way limited thereto. The scope of the present invention isnot limited methods related to the formation of aryl ethers. In itsbroadest sense, the present invention includes the use of aphosphazenium salt in any and all multiphase reaction mixtures in whichthe phosphazenium salt functions as a phase transfer catalyst.

As noted, in one aspect the present invention relates to a method formaking aromatic ethers. More particularly, the present invention relatesto preparation of the aromatic ethers by contacting in a multiphasereaction mixture the salt of at least one aromatic hydroxy compound withat least one aromatic compound comprising at least one leaving group,said reaction mixture comprising a phosphazenium salt phase transfercatalyst.

In one embodiment, the phosphazenium salt has structure I

wherein n is an integer from zero to about 10, R¹ and R² areindependently selected from the group consisting of C₁-C₂₀ aliphaticradicals, C₃-C₂₀ cycloaliphatic radicals, and C₄-C₂₀ aromatic radicals,and wherein said R¹ and R² may be linked together form a cyclicstructure comprising at least one nitrogen atom, and wherein X⁻ isselected from the group consisting of monovalent inorganic anions,monovalent organic anions, polyvalent inorganic anions, polyvalentorganic anions, and mixtures thereof.

The positive charge in the cation shown in structure I is represented ina canonical form in which the positive charge is localized on aphosphorous atom. Those skilled in the art will understand that numerouscanonical forms other than that featured in structure I are possible,and that the positive charge is considered to be delocalized over thewhole molecule.

In one embodiment, R¹ and R² in the phosphazenium salt represented bythe structure I are the same or different and each represents ahydrocarbon group having 1 to 10 carbon atoms, wherein R¹ and R² are atany occurrence independently selected from the group consisting ofaliphatic and aromatic hydrocarbon groups. For example, R¹ and R² may bemethyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, sec-butyl,tert-butyl, 2-butenyl, 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl,isopentyl, tert-pentyl, 3-methyl-2-butyl, neopentyl, n-hexyl,4-methyl-2-pentyl, cyclopentyl, cyclohexyl, 1-heptyl, 3-heptyl, 1-octyl,2-octyl, 2-ethyl-1-hexyl, 1,1-dimethyl-3,3-dimethylbutyl (popular name:tert-octyl), nonyl, decyl, phenyl, 4-toluoyl, benzyl, 1-phenylethyl, and2-phenylethyl. In one embodiment, R¹ and R² are aliphatic hydrocarbongroups having from 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl,isopropyl, tert-butyl, tert-pentyl and 1,1-dimethyl-3,3-dimethylbutyl.

In an alternate embodiment R¹ and R² together form a cyclic structurecomprising at least one nitrogen atom. In the case wherein both R¹ andR² are bound to the same nitrogen atom and both R¹ and R² representaliphatic radicals, R¹ and R² may together form a cyclic structurecomprising at least one nitrogen atom. Cyclic structures comprising oneor more nitrogen atoms are exemplified by the pyrrolidin-1-yl group, thepiperidin-1-yl group, the morpholin-4-yl group, and variants of thosegroups substituted by alkyl groups, for example methyl groups and ethylgroups.

In one embodiment the phosphazenium salt is selected from the groupconsisting of phosphazinum salts having structures II, III, IV, and V

wherein R¹, R² and X⁻ are defined as in structure I.

The anionic species X⁻ shown in structures I-V is selected from thegroup consisting of monovalent inorganic anions, monovalent organicanions, polyvalent inorganic anions, polyvalent organic anions, andmixtures thereof. Monovalent inorganic anions include chloride, bromide,fluoride, methanesulfonate, hydrogensulfate, bicarbonate, and the like.Polyvalent inorganic anions include carbonate, sulfate, sulfite, and thelike. Monovalent organic anions include methanesulfonate, acetate,alkoxide, acetylacetonate, and the like. Polyvalent organic anionsinclude malonate, succinate, ethylenedisulfonate (i.e. ⁻O₃SCH₂CH₂SO₃ ⁻),and the like.

In one embodiment of the present invention, the salt of at least onearomatic hydroxy compound is contacted with at least one aromaticcompound comprising at least one leaving group, said contacting beingcarried out in the presence of an effective amount of a phosphazeniumsalt having structure I. An effective amount of phosphazenium saltcatalyst is defined as that amount of phosphazenium salt required toaffect materially the outcome of the reaction. Typically, an effectiveamount of phosphazenium salt catalyst means an amount of phosphazeniumsalt needed to produce a measurable increase in a reaction rate,relative to the rate of reaction observed in the absence phosphazeniumsalt. In one embodiment, the phosphazenium salt is used in an amountcorresponding to between about 0.1 and about 10 mole percent based uponthe amount of the aromatic hydroxyl compound employed. In anotherembodiment, the phosphazenium salt is used in an amount corresponding tobetween about 0.2 and about 5 mole percent based upon the amount of thearomatic hydroxyl compound employed. In yet another embodiment, thephosphazenium salt is used in an amount corresponding to between about0.5 and about 2 mole percent based upon the amount of the aromatichydroxyl compound employed.

In one embodiment the salt of at least one aromatic hydroxy compound hasstructure VI

R³(ZM)_(k)  (VI)

wherein R³ is a C₅-C₄₀ aromatic radical; M is a metal selected from thegroup consisting of alkali metals, alkaline earth metals, and mixturesthereof; Z is oxygen, sulfur, or selenium, at least one Z being oxygen;and k is 1, 2 or 3.

Typically, the salt of at least one aromatic hydroxy compound is derivedfrom the corresponding hydroxy compound by deprotonation. In oneembodiment the at least one aromatic hydroxy compound is a dihydroxyaromatic compound of the formula VII

wherein A¹ is independently at each occurrence a C₃-C₂₀ aromaticradical; E is independently at each occurrence a bond, a C₁-C₂₀aliphatic radical, a C₃-C₂₀ cycloaliphatic radical, or a C₅-C₂₀ aromaticradical, a sulfur atom, a sulfinyl group, a sulfonyl group, a seleniumatom, or an oxygen atom; and t, s and u are independently integers from0-10 wherein at least one of t, s and u is not zero.

Suitable aromatic radicals “A¹” include, but are not limited to,phenylene, biphenylene, naphthylene, and the like. Suitable groups “E”include but are not limited to alkylene and alkylidene groups, forexample methylene, ethylene, ethylidene, propylene, propylidene,isopropylidene, butylene, butylidene, isobutylidene, amylene, amylidene,isoamylidene, and the like. The group “E” includes C₅-C₂₀ aromaticradicals for example the C₁₂ divalent aromatic radical represented bystructure VIII, the dashed lines (Structure VIII) indicating the pointsof attachment of the radical to the A¹ groups shown in structure VII.

The group “E” may also be a tertiary nitrogen linkage; an ether linkage;a carbonyl linkage; a silicon-containing linkage, silane, siloxy; or asulfur-containing linkage including, but not limited to, sulfide,sulfoxide, sulfone, and the like; or a phosphorus-containing linkageincluding, but not limited to, phosphinyl, phosphonyl, and the like. Inother embodiments E may be a cycloaliphatic group including, but notlimited to, 1,1-cyclopentylidene; 1,1-cyclohexylidene;3,3,5-trimethyl-1,1-cyclohexylidene; 3-methyl-1,1-cyclohexylidene;2-[2.2.1]-bicycloheptylidene, neopentylidene, cyclopentadecylidene,cyclododecylidene, adamantylidene, and the like.

In one embodiment the dihydroxy aromatic compound represented bystructure VII, E may be an unsaturated alkylidene group. Suitabledihydroxy-substituted aromatic hydrocarbons of this type include thoseof the formula IX:

wherein independently each R⁴ is independently at each occurrencehydrogen, chlorine, bromine, fluorine, or a C₁₋₂₀ monovalent aliphaticradical (for example a methyl group, a t-butyl group, or a methoxygroup), and each Y is independently at each occurrence hydrogen,chlorine, bromine, or fluorine.

Suitable dihydroxy-substituted aromatic hydrocarbons also include thoseof the formula X:

wherein each R⁴ is independently hydrogen, chlorine, bromine, fluorine,or a C₁₋₂₀ monovalent aliphatic radical (for example a methyl group, at-butyl group, or a methoxy group), and R^(g) and R^(h) areindependently hydrogen, a C₁-C₂₀ aliphatic radical, a C₃-C₂₀cycloaliphatic radical, or a C₄-C₂₀ aromatic radical. Further R^(g) andR^(h) may together form a C₄-C₂₀ cycloaliphatic radical.

In some embodiments of the present invention, dihydroxy-substitutedaromatic hydrocarbons that may be used comprise those disclosed by nameor formula (generic or specific) in U.S. Pat. Nos. 2,991,273; 2,999,835;3,028,365; 3,148,172; 3,153,008; 3,271,367; 3,271,368; and 4,217,438. Inother embodiments of the invention, dihydroxy-substituted aromatichydrocarbons comprise bis(4-hydroxyphenyl)sulfide;bis(4-hydroxyphenyl)ether; bis(4-hydroxyphenyl)sulfone;bis(4-hydroxyphenyl)sulfoxide; 1,4-dihydroxybenzene; 4,4′-oxydiphenol;2,2-bis(4-hydroxyphenyl)hexafluoropropane;4,4′-(3,3,5-trimethylcyclohexylidene)diphenol;4,4′-bis(3,5-dimethyl)diphenol;1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane;4,4-bis(4-hydroxyphenyl)heptane; 2,4′-dihydroxydiphenylmethane;bis(2-hydroxyphenyl)methane; bis(4-hydroxyphenyl)methane;bis(4-hydroxy-5-nitrophenyl)methane;bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane;1,1-bis(4-hydroxyphenyl)ethane; 1,2-bis(4-hydroxyphenyl)ethane;1,1-bis(4-hydroxy-2-chlorophenyl)ethane;2,2-bis(3-phenyl-4-hydroxyphenyl)propane;2,2-bis(4-hydroxy-3-methylphenyl)propane;2,2-bis(4-hydroxy-3-ethylphenyl)propane;2,2-bis(4-hydroxy-3-isopropylphenyl)propane;2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane;3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane;bis(4-hydroxyphenyl)cyclohexylmethane;2,2-bis(4-hydroxyphenyl)-1-phenylpropane; 2,4′-dihydroxyphenyl sulfone;2,5-dihydroxy naphthalene; 2,6-dihydroxy naphthalene; hydroquinone;resorcinol; C₁₋₃ alkyl-substituted resorcinols; 4-methyl resorcinol;catechol; 1,4-dihydroxy-3-methylbenzene; 2,2-bis(4-hydroxyphenyl)butane;2,2-bis(4-hydroxyphenyl)-2-methylbutane;1,1-bis(4-hydroxyphenyl)cyclohexane; 4,4′-dihydroxydiphenyl;2-(3-methyl-4-hydroxyphenyl)-2-(4-hydroxyphenyl)propane;2-(3,5-dimethyl-4-hydroxyphenyl)-2-(4-hydroxyphenyl)propane;2-(3-methyl-4-hydroxyphenyl)-2-(3,5-dimethyl-4-hydroxyphenyl)propane;bis(3,5-dimethylphenyl-4-hydroxyphenyl)methane;1,1-bis(3,5-dimethylphenyl-4-hydroxyphenyl)ethane;2,2-bis(3,5-dimethylphenyl-4-hydroxyphenyl)propane;2,4-bis(3,5-dimethylphenyl-4-hydroxyphenyl)-2-methylbutane;3,3-bis(3,5-dimethylphenyl-4-hydroxyphenyl)pentane;1,1-bis(3,5-dimethylphenyl-4-hydroxyphenyl)cyclopentane;1,1-bis(3,5-dimethylphenyl-4-hydroxyphenyl)cyclohexane;bis(3,5-dimethyl-4-hydroxyphenyl) sulfoxide;bis(3,5-dimethyl-4-hydroxyphenyl) sulfone;bis(3,5-dimethylphenyl-4-hydroxyphenyl)sulfide; and like bisphenols. Ina particular embodiment the dihydroxy-substituted aromatic hydrocarbonis bisphenol A.

In some embodiments the dihydroxy-substituted aromatic compoundsrepresented by structure VII includes compounds comprising one or morefused rings represented by component “E”, attached to one or morearomatic groups A¹. Suitable dihydroxy-substituted aromatic hydrocarbonsof this type include those containing indane structural units such asrepresented by the formula (XI),3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol; and by the formula (XII),1-(4-hydroxyphenyl)-1,3,3-trimethylindan-5-ol.

Also included with the class of dihydroxy aromatic compounds representedby formula VII are bisphenols comprising spirocyclic structures ascomponent “E”, for example as in2,2,2′,2′-tetrahydro-1,1′-spirobi[1H-indene]diol.

The term “alkyl” as used in the various embodiments of the presentinvention falls within the definition of an “aliphatic radical” asdefined herein and includes both linear alkyl groups such as methylgroups, and branched alkyl groups such as isobutyl groups.

The salt of at least one aromatic hydroxy compound employed in thepresent invention is typically a sodium or potassium salt. Sodium saltsare often used in particular embodiments by reason of their availabilityand relatively low cost. In one embodiment, the salt of at least onearomatic hydroxy compound is a disodium salt of a dihydroxy aromaticcompound.

In one embodiment the salt of the aromatic hydroxy compound is generatedin-situ, from an organic compound which is not itself an aromatichydroxy compound. For example, the salt of hydroxyimide XIII may beformed in-situ from the corresponding chloroimide. For example,4-chloro-N-methylphthalimide reacts with sodium hydroxide in a reactionmixture comprising a phosphazenium salt phase transfer catalyst toafford 4-hydroxy-N-methylphthalimide which is then deprotonated bysodium hydroxide, typically at a rate faster than its formation, toafford the corresponding sodium salt. Alternately,4-chloro-N-methylphthalimide reacts with an oxygen nucleophile such aspotassium carbonate or sodium acetate to afford an intermediate whichsubsequently converted to the salt of hydroxyimide XIII. In aromatichydroxy compounds represented by

structure XIII, R⁵ is typically an organic radical selected from thegroup consisting of C₁-C₁₂ aliphatic radicals, C₃-C₁₂ cycloaliphaticradicals, and C₄-C₃₀ aromatic radicals. In an alternate embodiment, thearomatic hydroxy compound has the formula XIV.

The reaction may be performed in the absence a solvent, or alternativelyin the presence of a solvent. Preferably, the reaction is carried out inthe presence of at least one inert solvent. Suitable solvents includenon-polar solvents and polar aprotic solvents (also referred to as“dipolar aprotic solvents”). Typically, the reaction is carried out inan aromatic solvent, for example an aromatic hydrocarbon solvent orchloroaromatic solvent. In one embodiment the solvent has a boilingpoint above about 120° C., preferably above about 150° C., and morepreferably above about 180° C. Suitable solvents include, but are notlimited to, toluene, xylene, ortho-dichlorobenzene (o-DCB),para-dichlorobenzene, dichlorotoluene; 1,2,4-trichlorobenzene;diphenylether, dimethylsulfone, diphenyl sulfone, sulfolane, phenetole,anisole, veratrole, and mixtures thereof. In a preferred embodimentchlorinated aromatic liquids be employed as solvents, examples of whichinclude, but are not limited to, ortho-dichlorobenzene (o-DCB);2,4-dichlorotoluene; and 1,2,4-trichlorobenzene. In some embodiments2,4-dichlorotoluene is a preferred solvent. In the case of somesolvents, such as ortho-dichlorobenzene, the proportion of phasetransfer catalyst can be increased and/or the reaction can be run atsuperatmospheric pressure to permit higher temperatures and higherreaction rates.

Typically, the aromatic compound comprising at least one leaving groupis a compound having formula XV, wherein Ar¹ is independently at eachoccurrence a C₃-C₂₀ aromatic radical, L¹ is a leaving groupindependently selected from the group consisting of fluoro, chloro,bromo, iodo, nitro, and organosulfonate groups; B is an activatinggroup, and g is 1, 2 or 3. Organosulfonate groups are illustrated by themethanesulfonate (MeSO₃—), tosylate (C₇H₇SO₃—), andtrifluoromethanesulfonate (CF₃SO₃—) groups.

In one embodiment the aromatic radical Ar¹ is a monocyclic aromaticradical, for example a phenylene (C₄H₄) radical, L¹ is a chlorine atom,B is a sulfonyl group, and g is 2. The activating group B, is typicallyan electron-withdrawing group, which may be monovalent or polyvalentgroup. The activating group B is illustrated by halo, nitro, acyl,cyano, carboxy, carbonyl, alkoxycarbonyl, aldehydro, sulfonyl, andperfluoroalkyl. In addition B may be a heterocyclic aromatic activatinggroup such as pyridyl. Examples of divalent groups which may serve ascomponent “B” in structure XV include the carbonyl group,carbonylbis(arylene) groups, sulfonyl groups, bis(arylene) sulfonegroups, benzo-1,2-diazine groups, and azoxy groups. When “g” instructure XV is 2, the moiety “—Ar¹—B—Ar¹-” is illustrated by abis(arylene) sulfone moiety, a bis(arylene) ketone moiety, abis(arylene)benzo-1,2-diazine moiety, and a bis(arylene)azoxy moiety.

Compounds represented by structure XV include compounds whereincomponent “B” together with Ar¹, form a fused ring system such asbenzimidazole, benzoxazole, quinoxaline or benzofuran. In suchcompounds, L¹ includes leaving groups such as fluoro, chloro, bromo,iodo, nitro groups. Fluoro and chloro groups are frequently preferred.

In one embodiment, the aromatic compound comprising at least one leavinggroup is a is a bisimide having structure XVI

wherein L¹ is defined as in structure XV, and R⁶ is selected from thegroup consisting of divalent C₁-C₁₂ aliphatic radicals, divalent C₃-C₁₂cycloaliphatic radicals, and divalent C₄-C₃₀ aromatic radicals.

In a further embodiment R⁶ is a divalent aromatic radical havingstructure XVII

wherein Q is a C₁-C₁₂ aliphatic radical, a C₃-C₁₂ cycloaliphaticradical, a C₄-C₁₈ aromatic radical, an oxygen, atom, a sulfur atom, asulfinyl group, a sulfonyl group, a selenium atom or a bond. In apreferred embodiment R⁶ is selected from the group consisting ofm-phenylene, p-phenylene, 4,4′-oxybis(phenylene).

In an alternate embodiment the aromatic compound comprising at least oneleaving group is selected from the group consisting of compounds havingformula XVIII

wherein G is a carbonyl group (—CO—), or a sulfonyl group (—SO₂—); L² isindependently at each occurrence a fluoro, chloro, bromo, iodo, nitro,or a trifluormethansulfonate group; and “m” and “p” are independentlyintegers from 0-5, wherein not both m and p are zero.

In one embodiment the aromatic compound comprising at least one leavinggroup is selected from the group consisting of bis(4-fluorophenyl)sulfone, bis(4-chlorophenyl) sulfone, bis(4-fluorophenyl) ketone, andbis(4-chlorophenyl) ketone.

In an alternate embodiment the aromatic compound comprising at least oneleaving group is selected from the group consisting of 1,3- and1,4-bis[N-(4-fluorophthalimido)]benzene and4,4′-bis[N-(4-fluorophthalimido)]phenyl ether and the correspondingchloro, bromo and nitro compounds.

In yet another embodiment the aromatic compound comprising at least oneleaving group is selected from the group of substituted aromatic imideshaving structure XIX

wherein R⁷ is selected from the group consisting of monovalent C₁-C₁₂aliphatic radicals, monovalent C₃-C₁₂ cycloaliphatic radicals, andmonovalent C₄-C₃₀ aromatic radicals; and L² is a fluoro, chloro, bromo,iodo, or nitro group. Suitable substituted aromatic imides include3-choro-N-methylphthalimide, 4-choro-N-methylphthalimide,3-fluoro-N-butylphthalimide, 4-fluoro-N-butylphthalimide,3-choro-N-cyclohexylphthalimide, 4-choro-N-cyclohexylphthalimide,3-chloro-N-phenylphthalimide, 4-chloro-N-phenylphthalimide, and thelike.

In yet another embodiment the aromatic compound comprising at least oneleaving group is selected from the group of substituted phthalicanhydrides XX

wherein L² is a fluoro, chloro, bromo, iodo, or nitro group. Suitablesubstituted phthalic anhydrides include, 3-chlorophthalic anhydride,4-chlorophalic anhydride, 3-fluorophthalic anhydride, and the like.

In yet still another embodiment, the aromatic compound comprising atleast one leaving group is selected from the group of compoundsrepresented by structures XXI and XXII

wherein D is independently at each occurrence a carbonyl group or asulfonyl group, and L³ is independently at each occurrence a fluoro,chloro, bromo, iodo, or nitro group. Compounds XXI are illustrated bythe PEEK monomers1,1′-(p-phenylenedioxy)bis[4-(4-chlorobenzoyl)]benzene;1,1′-(p-phenylenedioxy)bis[4-(4-fluorobenzoyl)]benzene, and the like.Compounds XXII are illustrated by 1,3-bis(4-chlorobenzoyl)benzene;1,3-bis(4-fluorobenzoyl)benzene; 1,4-bis(4-chlorobenzoyl)benzene;1,3-bis(4-chlorophenylsulfonyl)benzene; and the like.

When the reaction between the salt of at least one aromatic hydroxycompound and at least one aromatic compound comprising at least oneleaving group is complete, the product aromatic ether may be isolated byconventional techniques. It is often convenient to filter the productmixture while still hot to remove insoluble by-products, andsubsequently cool the filtrate, whereupon the desired aromatic etherprecipitates and may be collected by filtration.

In one embodiment the contacting in a reaction mixture the salt of atleast one aromatic hydroxy compound with at least one aromatic compoundcomprising at least one leaving group is carried out at a temperature ina range from about 50° C. to about 250° C., preferably from about 120°C. to about 250° C., and still more preferably from about 150° C. toabout 250° C. In an alternate embodiment the contacting is carried outat a temperature range from about 150° C. to about 225° C. Typically,the contacting is carried out at atmospheric pressure under inertatmosphere, for example under a nitrogen atmosphere.

EXAMPLES

The following examples are set forth to provide those of ordinary skillin the art with a detailed description of how the methods claimed hereinare evaluated, and are not intended to limit the scope of what theinventors regard as their invention. Unless indicated otherwise, partsare by weight, and temperature is in ° C.

Yields in the reactions of 4-chlorophenyl phenyl sulfone were determinedusing an internal standard HPLC method. These reactions are at timesreferred to as “model” reactions since they often predict (or model) thebehavior of more complex polymerization reactions. Phenanthrene was usedas the internal standard in all cases, and was added to the reactionsalong with the reactants. Aliquots of the reaction mixture were removedperiodically during the reaction, and quenched with 2 drops of aceticacid. The quenched aliquots were diluted with 2 milliliters oftetrahydrofuran (hereinafter known as “THF”), filtered, and analyzed ona Zorbax 150 cm×4.6 mm C-8 column, eluting with a THF-water gradient.Recovered bisphenol A, solvent, phenanthrene, starting substrate, andproduct bis-sulfone were separated, and the amount of starting materialand product could be quantified by comparing to the internal standard.The HPLC was calibrated by using pure isolated bis-sulfone productrelative to phenanthrene. No mono-substitution product was noted in anycase.

Gel permeation chromatography (hereinafter known as GPC)characterization was carried out using Turbogel® Software on acommercial GPC system using a Polymer Labs Mixed C column, at a columntemperature of 40° C., eluting with 3% isopropanol/chloroform at 0.7milliliter per minute, using an Agilent HPLC pump and UV detection at255 nm. The system was calibrated with polystyrene standards daily,using a third order fit. The correlation coefficient was typically about0.9996. Sample size was 5-10 microliters. Two to three drops of polymersolution were added to 2 drops acetic acid in approximately 0.25 mLo-dichlorobenzene, to quench the polymerization reaction. The sample wasdiluted with 1 milliliter of chloroform, rinsing the pipette withsufficient chloroform to ensure that all of the product polymer wasdissolved. Water (1 milliliter) was added with stiffing to dissolve theby-product sodium chloride. Ten drops of the lower (chloroform) phasewere added to a sample filter, diluted with 1 milliliter of chloroformand filtered through a 0.45 micron polytetrafluoroethylene membrane. Thecontents were placed directly into a sampling vial, and analyzed by GPC.Molecular weights are reported as number average (M_(n)) or weightaverage (M_(w)) molecular weight.

Preparation of Phosphazenium Salt

A phosphazene base, P 2-Ethyl[1-ethyl-2,2,4,4,4-pentakis(dimethylamino)-2×5,4×5-catenadi(phosphazene)](CAS No.:165535-45-5, Aldrich Chemical Co., 679 mg; 2.0 millimoles) wasdissolved in 5 milliliters of chloroform and cooled to 0° C. About 2.0mmol of methyl methanesulfonate (178 μL) was added to the above solutionwhile maintaining the temperature at 0° C. The proton NMR was recordedat the end of one hour of reaction, and indicated that all of themethylsulfonate had reacted. The solvent was removed by rotaryevaporation and o-dichlorobenzene (o-DCB) was added. The resultingsolution was heated and a small amount of o-DCB was distilled in orderto dry the solution of the phosphazenium salt. The concentration of thephosphazenium salt was determined by proton NMR.

General Procedure for Model Reactions (Displacement Reactions of4-chlorophenyl phenyl sulfone)

Dry bisphenol A disodium salt (BPANa₂) was weighed into a 50-mL flask,and a 2 mole % excess of 4-chlorophenyl phenyl sulfone was added. Thetransfers were carried out in a dry box. The flask was capped, removedfrom the dry box, and was fitted with a condenser and a nitrogen purge.Sufficient solvent was added to achieve a final product concentration toapproximately 20 weight %, assuming quantitative conversion of startingmaterials to product. Phenanthrene was added (typically 100 mg) as aninternal standard. The reaction mixture was stirred magnetically whilebeing heated to reflux. Once reflux had been achieved, the phasetransfer catalyst (PTC) was added, and the timer was started. Sampleswere removed periodically, and were analyzed by HPLC.

FIGS. 1 and 2 illustrate the behavior of the new phase transfercatalysts in the formation of1,1′-(1-methylethylidene)bis[4-[4-(phenylsulfonyl)phenoxy]benzene (CASNo. 90139-53-0). When the P2-EthylMethyl mesylate was used as a PTC at1.0 mole % in the model reaction in refluxing o-DCB at 180° C. (See 4(FIG. 1)), the reaction exhibited pseudo-first order kinetics. Thisindicates that no catalyst decomposition nor diminution in rate wasoccurring during the reaction. In order to further test the stability ofthe phosphazenium salt, similar reactions were carried out at highertemperatures, in 3,4-dichlorotoluene (bp=200° C.) (See 6 (FIG. 1)) andin 1,2,4-trichlorobenzene (bp=214° C.) (See 2 (FIG. 1)). As shown inFIG. 1, even at 200° C., essentially linear reaction kinetics wereobserved, indicating no decomposition of the P2-EthylMethyl mesylatephase transfer catalyst. In trichlorobenzene, only a small amount ofdecomposition was observed, after 60 minutes (See 2 (FIG. 1)). In thisinstance only 0.5 mole % catalyst was used, since after initialrange-finding experiments it was determined that reaction using 1.0 mole% would be too fast to follow accurately at 214° C.

The results shown in FIG. 1 illustrate that because they are highlystable, the phosphazenium salt phase transfer catalysts are effectiveover a broad range of temperatures. Under the reaction conditionsexamined (2, 4, 6 FIG. 1) the stability of the phosphazenium saltcatalyst was observed to be superior relative to a representativeguanidinium salt phase transfer catalyst, hexaethylguanidium chloride(HEGCl). FIG. 2 illustrates the enhanced stability of the phosphazeniumcatalysts and compares a reaction utilizing HEGCl in o-DCB at 180° C.(See 10 FIG. 2) to the same reaction using a phosphazenium catalyst ateither 180° C. (See 20 FIG. 2) or at 200° C. (See 30 FIG. 2). AlthoughHEGCl provides a faster initial rate (See 12 FIG. 2) than thephosphazenium salt at 180° C. (See 22 FIG. 2), the reactionsincorporating a phosphazenium salt phase transfer catalyst ultimatelygive higher yields (Compare 18, 28, and 36 FIG. 2). At 200° C. (30, FIG.2), the rate increase obtained by increasing the reaction temperaturemore than compensates for the relative effectiveness of the catalysts,and reaction rates faster than could be achieved with HEGCl wereobtained (Compare 12 and 32 FIG. 2).

General Procedure for PTC Mediated Polymerization

An accurately weighed amount (typical lab-scale amounts wereapproximately 10 grams) of bisphenol A disodium salt (abbreviated hereas BPANa₂) was transferred in a dry box into an oven-dried, 250-mL,3-necked flask. (An electronic balance, capable of 0.1 mg accuracy wasused in the dry box). The flask was capped and transferred to an oilbath maintained at 205° C., at which point it was fitted with a nitrogensparge tube atop a reflux condenser, a mechanical stirrer, and adistillation apparatus. The required amount of solvent to provide asolution of 30 wt % polymer in solvent, plus an additional 20 mL wasadded to the flask. The solvent was distilled at atmospheric pressure,while checking the distillate by Karl-Fischer titration to ensuredryness. If Karl-Fischer titration of the distillate indicated the saltwas dry after the 20 mL solvent had distilled, then the required amountof 4,4′-dichlorodiphenylsulfone was added, along with an additional 10mL of solvent. Again, the excess solvent was distilled, affording aslurry of reactants in dry solvent. At this stage there was no evidencethat any displacement reaction had occurred. Upon the addition of thecatalyst in dry o-DCB solution, the displacement reaction initiated, andtiming was begun. Samples were removed periodically and analyzed by GPCanalysis. When the desired weight average molecular weight (M_(w)) wasmet, the reaction was quenched by the addition of approximately 0.5 mLof phosphoric acid.

FIGS. 3 and 4 illustrate the effectiveness of the phosphazenium catalystin polymerization reactions (See 42 FIGS. 3 and 50 FIG. 4). Theefficiency of catalysis is readily apparent. In FIG. 3, the reaction wasrun in o-DCB at 180° C. using 1 mole percent of the phosphazeniumcatalyst. After 30 minutes at 180° C. an additional 1 mole percent ofthe phosphazenium catalyst was added. The additional catalyst resultedin the significant rate enhancement observed at 40 (FIG. 3) and themolecular weight of the growing polymer chain was greater than 40,000daltons in less than 90 minutes.

FIG. 4 illustrates the same reaction in a higher boiling solvent,dichlorotoluene, at 200° C. In the reaction only 1 mole % phosphazeniumcatalyst was employed. The molecular weight of the growing polymer chainin the reaction illustrated in FIG. 4 was greater than 40,000 daltons inless than 60 minutes.

Further evidence that the phosphazenium salt phase transfer catalysts ofthe present invention show enhanced stability and effectiveness relativeto guanidinium catalysts (e.g. HEGCl) is illustrated by the followingexamples. Whereas polymerization of an 80/20 biphenol/BPA mixturerequired 500-700 minutes to reach Mw approximately 50,000 using 2.0 mole% HEGCl in refluxing o-DCB, similar reaction using BPANa₂ reached 54,000in just 120 minutes. Reducing the phosphazenium catalyst level to 1.0%and increasing the reaction temperature to 200° C. by carrying out thereaction in refluxing dichlorotoluene also gave excellent results: Thepolymer reached Mw=51,650 daltons in just 2 hours. Similar reactionusing 1% HEGCl in o-DCB required more than 40 hours to reach that Mw.Thus, it has been found that because of the enhanced stability of thephosphazenium catalysts of the present invention, the rates of chemicalreactions employing said catalysts can be increased merely by increasingthe reaction temperature without destroying the catalyst. Further, theenhanced stability of the phosphazenium catalysts of the presentinvention provides for a reduction in the amount of catalyst need inreactions employing phase transfer catalysts.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood by thoseskilled in the art that variations and modifications can be effectedwithin the spirit and scope of the invention.

1. A method for making an aromatic polyether composition, said methodcomprising contacting in a reaction mixture the salt of at least onearomatic dihydroxy compound with at least one aromatic compound bearingat least two leaving groups, said contacting being carried out in thepresence of a phosphazenium salt having structure I

wherein n is an integer from zero to about 10, R¹ and R² areindependently selected from the group consisting of C₁-C₂₀ aliphaticradicals, C₃-C₂₀ cycloaliphatic radicals, and C₄-C₂₀ aromatic radicals,and wherein said R¹ and R² may be linked together form a cyclicstructure comprising at least one nitrogen atom, and wherein X⁻ isselected from the group consisting of monovalent inorganic anions,monovalent organic anions, polyvalent inorganic anions, polyvalentorganic anions, and mixtures thereof.
 2. The method according to claim 1wherein said aromatic dihydroxy compound is selected from the groupconsisting of bisphenol A, and 4,4′-biphenol.
 3. The method according toclaim 1 wherein said aromatic compound bearing at least two leavinggroups has formula XVIII

G is a carbonyl group, or a sulfonyl group; L² is independently at eachoccurrence a fluoro, chloro, bromo, iodo, nitro, or atrifluormethansulfonate group; and “m” and “p” are independentlyintegers from 0-5, wherein not both m and p are zero.
 4. The methodaccording to claim 1 wherein said contacting further comprises heatingto a temperature in a range between about 50 and 250° C.
 5. The methodaccording to claim 1 wherein said contacting further comprises heatingin the presence of an inert solvent to a temperature in a range betweenabout 50 and about 250° C.
 6. The method according to claim 5 whereinsaid inert solvent is selected from the group consisting ofortho-dichlorobenzene, para-dichlorobenzene, dichlorotoluene,1,2,4-trichlorobenzene, diphenyl sulfone, phenetole, anisole, veratrole,toluene, xylene, mesitylene and mixtures thereof.
 7. The methodaccording to claim 1 wherein said phosphazenium salt is present in anamount corresponding to between about 0.1 and 10 mole percent based onthe amount of aromatic hydroxy compound initially present in thereaction mixture.
 8. The method according to claim 1 wherein said saltof at least one aromatic hydroxy compound is of the formula VI:R³(ZM)_(k)  (VI) wherein R³ is a C₅-C₄₀ aromatic radical; M is a metalselected from the group consisting of alkali metals, alkaline earthmetals, and mixtures thereof; Z is oxygen, sulfur, or selenium, whereinat least one Z is oxygen; and k is 1, 2 or
 3. 9. The method according toclaim 1 wherein said salt of at least one aromatic hydroxy compound is asalt of a dihydroxy aromatic compound having formula VII:

wherein A¹ is independently at each occurrence a C₃-C₂₀ aromaticradical; E is independently at each occurrence a bond, a C₁-C₂₀aliphatic radical, a C₃-C₂₀ cycloaliphatic radical, or a C₅-C₂₀ aromaticradical, a sulfur atom, a sulfinyl group, a sulfonyl group, a seleniumatom, or an oxygen atom; and t, s and u are independently integers from0-10 wherein at least one of t, s and u is not zero.
 10. The methodaccording to claim 1 wherein said salt of at least one aromatic hydroxycompound is a sodium salt.
 11. The method according to claim 10 whereinsaid salt of at least one aromatic hydroxy compound is the disodium saltof bisphenol A.
 12. The method according to claim 1 wherein saidaromatic compound comprising at least two leaving groups has formula XV:

wherein Ar¹ is independently at each occurrence a C₃-C₂₀ aromaticradical, L¹ is a leaving group independently selected from the groupconsisting of fluoro, chloro, bromo, iodo, nitro, and organosulfonategroups; B is an activating group, and g is 2 or
 3. 13. The methodaccording to claim 1 wherein said aromatic compound comprising at leasttwo leaving groups has formula XVI

wherein L¹ is a leaving group independently selected from the groupconsisting of fluoro, chloro, bromo, iodo, and nitro groups; and R⁶ isselected from the group consisting of divalent C₁-C₁₂ aliphaticradicals, divalent C₃-C₁₂ cycloaliphatic radicals, and divalent C₄-C₃₀aromatic radicals.
 14. The method according to claim 13 wherein R⁶ is anaromatic radical having structure XVII

wherein Q is a C₁-C₁₂ aliphatic radical, a C₃-C₁₂ cycloaliphaticradical, a C₄-C₁₈ aromatic radical, an oxygen, atom, a sulfur atom, asulfinyl group, a sulfonyl group, a selenium atom or a bond.
 15. Themethod according to claim 1 wherein said salt of the aromatic dihydroxycompound is generated in-situ, from an organic compound which is notitself an aromatic dihydroxy compound.
 16. The method according to claim1 wherein said aromatic compound comprising at least two leaving groupsis selected from the group consisting of compounds having formula XXIand XXII

wherein in each of structures XXI and XXII D is independently at eachoccurrence a carbonyl group or a sulfonyl group, and L³ is independentlyat each occurrence a fluoro, chloro, bromo, iodo, or nitro group.